1. Field of the Invention
The present invention relates to an input/output port of a semiconductor integrated circuit device.
2. Description of the Related Art
When a semiconductor integrated circuit device transfers signals to and from an external device (an input/output device or another semiconductor integrated circuit device), the circuit of the semiconductor integrated circuit device may have an operating voltage that is different from that of the external device. In such a case, the voltage is converted by a voltage converting section provided in the input/output port of the semiconductor integrated circuit device.
An object of the present invention is to provide a semiconductor integrated circuit device having a port that functions as at least one of an input port and an output port, and that can operate at a high speed.
(1) In accordance with one embodiment of the present invention, a master slice type semiconductor integrated circuit device comprises a semiconductor substrate on which a circuit section is formed, and a port section connected with the circuit section. In one aspect, the port section functions as at least one of an input port and an output port. The port section may be provided with a voltage converting section for converting a first voltage into a second voltage that differs from the first voltage. The voltage converting section includes a first section having a first field effect transistor, and a second section having a second field effect transistor. A gate insulating layer of the first field effect transistor has a film thickness which differs from a film thickness of a gate insulating layer of the second field effect transistor.
When the thickness of the gate insulating layer is unnecessarily large, the operation of the field effect transistor becomes slow because the channel forming speed slows down. The gate insulating layer of the first field effect transistor in the first section of the voltage converting section has the thickness which differs from that of the gate insulating layer of the second field effect transistor in the second section of the voltage converting section. As a result, the thickness of the gate insulating layer that matches a given voltage can be selected in the voltage converting section. The operating speed of the port section can thus be increased.
The circuit section may be any one of a logic circuit, ROM, RAM, or analog circuit, or a combination of these.
(2) In one embodiment, the voltage converting section may function as an output port and include a predriver for inputting and outputting a first voltage signal, and a driver for inputting and outputting a second voltage signal. The predriver has a wave shaping function for a signal transmitted from the circuit section. An external input device, output device, input/output device, or another semiconductor integrated circuit device are driven by the driver.
(3) In one embodiment, the voltage converting section may comprise a level shifter; the first section of the voltage converting section may comprise a first part of the level shifter; the first voltage signal may be input in and output from the first part of the level shifter; the second section of the voltage converting section may comprise a second part of the level shifter; and the first voltage signal may be input in and the second voltage signal may be output from the second part of the level shifter. The level shifter is an example of a voltage converting section.
(4) In one embodiment, the predriver may be connected with the circuit section and the first part of the level shifter, and the driver may be connected with the second part of the level shifter.
(5) In one embodiment, the thickness of a gate insulating layer of the field effect transistor being a component of the predriver may be equal to (or substantially the same as) the thickness of a gate insulating layer of the first field effect transistor being a component of the level shifter. Also, the thickness of a gate insulating layer of the field effect transistor being a component of the driver may be equal to (or substantially the same as) the thickness of a gate insulating layer of the second field effect transistor being a component of the level shifter. In one embodiment, the gate insulating layers of field effect transistors in which the same voltage is applied to their respective gate electrodes may have the same thickness.
(6) In one embodiment, the circuit section may be operated by the first voltage; and the thickness of a gate insulating layer of the field effect transistor being a component of the circuit section, the thickness of the gate insulating layer of the field effect transistor being the component of the predriver, and the thickness of the gate insulating layer of the first field effect transistor being the component of the first part of the level shifter may be equal to one another. In one embodiment, the gate insulating layers of field effect transistors in which the same voltage is applied to their respective gate electrodes may have the same thickness.
(7) In one embodiment, a region where the predriver and the first part of the level shifter are formed may be located between a region where the circuit section is formed and a region where the driver and the second part of the level shifter are formed.
The semiconductor integrated circuit device has many regions where various field effect transistors are formed. For example, in one region, the first voltage is applied to gate electrodes of the filed effect transistors (e.g., the predriver and the first part of the level shifter, and the circuit section). In another region, the second voltage is applied to gate electrodes of the field effect transistors (e.g., the driver and the second part of the level shifter). In accordance with the present invention, these regions can be disposed with reduced complexity. Accordingly, the device structure achieved by the present invention is advantageous in a gate array and an embedded array.
(8) In one embodiment, on the semiconductor substrate, the region where the predriver and the first part of the level shifter are formed may be located outside the region where the circuit section is formed. Further, the region where the driver and the second part of the level shifter are formed may be located outside the region where the predriver and the first part of the level shifter are formed.
(9) In one embodiment, the port section functions as an input port.
(10) In one embodiment, the voltage converting section may comprise a level shifter. In this embodiment, the first section of the voltage converting section may comprise a second part of the level shifter; and the first voltage signal may be input into and output from the second part of the level shifter. The second section of the voltage converting section may comprise a first part of the level shifter; and the second voltage signal may be input into and the first voltage signal may be output from the first part of the level shifter. The level shifter is an example of a voltage converting section.
(11) In one embodiment, the circuit section may be operated by the first voltage. In this embodiment, the thickness of a gate insulating layer of the field effect transistor being a component of the circuit section may be equal to the thickness of a gate insulating layer of the first field effect transistor being a component of the second part of the level shifter. In one embodiment, the gate insulating layers of field effect transistors that are operated with the same operating voltage may have the same thickness.
(12) In one embodiment, a region where the second part of the level shifter is formed may be located between a region where the circuit section is formed and a region where the first part of the level shifter is formed.
As a result, the this embodiment reduces the complexity in arranging regions where various field effect transistors that are operated with the first voltage and the second voltage are formed. For example, in one of the regions, the first voltage is applied to gated electrodes of the field effect transistors (e.g., the second part of the level shifter and the circuit section). In another region, the second voltage is applied to gate electrodes of the field effect transistors (e.g., the first part of the level shifter). These regions can be arranged with a less complexity. This brings about an advantage in the use of a gate array and an embedded array.
(13) In one embodiment, on the semiconductor substrate, the region where the second part of the level shifter is formed may be located outside the region where the circuit section is formed. Also, the region where the first part of the level shifter is formed may be located outside the region where the second part of the level shifter is formed.
(14) In one embodiment, the port section may function as an input port and an output port.
(15) In one embodiment, the port section may be provided with another voltage converting section; the input port of the port section may comprise the other voltage converting section; and the output port of the port section may comprise the voltage converting section.
(16) In one embodiment, the other voltage converting section may comprise a first section having a third field effect transistor, and a second section having a fourth field effect transistor. The gate insulating layer of the third field effect transistor may have the same thickness as the gate insulating layer of the first field effect transistor. The gate insulating layer of the fourth field effect transistor may have the same thickness as the gate insulating layer of the second field effect transistor. The gate insulating layers of field effect transistors in which the same voltage is applied to their gate electrodes may have the same thickness.
(17) In one embodiment, the voltage converting section may comprise a level shifter. The first section of the voltage converting section may comprise the first part of the level shifter, and the first voltage signal may be input into and output from the first part of the level shifter. The second section of the voltage converting section may comprise the second part of the level shifter; and the first voltage signal may be input into and the second voltage signal may be output from the second part of the level shifter. The first section of the other voltage converting section may comprise the second part of the other level shifter; and the first voltage signal may be input into and output from the second part of the other level shifter. The second section of the other voltage converting section may comprise a first part of the other level shifter; and the second voltage signal may be input into and the first voltage signal may be output from the first part of the other level shifter. The level shifter is an example of the voltage converting section, and the other level shifter is an example of the other voltage converting section.
(18) In one embodiment, the port section may comprise a predriver for inputting and outputting a first voltage, and a driver for inputting and outputting a second voltage. The input port of the port section may comprise the other level shifter; and the output port of the port section may comprise the predriver, the driver, and the level shifter.
(19) In one embodiment, the predriver may be connected with the circuit section and the first part of the level shifter; and the driver may be connected with the second part of the level shifter.
(20) In one embodiment, the thickness of a gate insulating layer of the field effect transistor being a component of the predriver, the thickness of a gate insulating layer of the first field effect transistor being a component of the first part of the level shifter, and the thickness of a gate insulating layer of the third field effect transistor being a component of the second part of the other level shifter, may be equal to one another. Also, the thickness of a gate insulating layer of the field effect transistor being a component of the driver, the thickness of a gate insulating layer of the second field effect transistor being a component of the second part of the level shifter, and the thickness of a gate insulating layer of the fourth field effect transistor being a component of the first part of the other level shifter, may be equal to one another. The gate insulating layers of field effect transistors in which the same voltage is applied to their gate electrodes may have the same thickness.
(21) In one embodiment, the circuit section may be operated by the first voltage. In this embodiment, the thickness of a gate insulating layer of the field effect transistor being a component of the circuit section, the thickness of the gate insulating layer of the field effect transistor being the component of the predriver, and the thickness of the gate insulating layer of the first field effect transistor being the component of the first part of the level shifter, and the thickness of the gate insulating layer of the third field effect transistor being the component of the second part of the other level shifter, may be equal to one another. The gate insulating layers of field effect transistors in which the same voltage is applied to their gate electrodes may have the same thickness.
(22) In one embodiment, a region where the predriver, the first part of the level shifter, and the second part of the other level shifter are formed may be located between a region where the circuit section is formed and a region where the driver, the second part of the level shifter, and the first part of the other level shifter are formed.
This embodiment reduces the complexity in arranging regions where various field effect transistors that are operated with the first voltage and the second voltage are formed. For example, in one of the regions, the first voltage is applied to gated electrodes of the field effect transistors (e.g., the circuit section, the predriver, the first part of the level shifter, and the second part of the other level shifter). In another region, the second voltage is applied to gate electrodes of the field effect transistors (e.g., the second part of the level shifter, the first part of the other level shifter, and the driver). These regions can be arranged with a less complexity. This brings about an advantage in the use of a gate array and an embedded array.
(23) In one embodiment, on the semiconductor substrate, the region where the predriver, the first part of the level shifter, and the second part of the other level shifter are formed may be located outside the region where the circuit section is formed. Also, the region where the driver, the second part of the level shifter, and the first part of the other level shifter are formed may be located outside the region where the predriver, the first part of the level shifter, and the second part of the other level shifter are formed.
(24) In one embodiment, each of the circuit section and the port section may comprise at least one of a gate array and an embedded array.
(25) In one embodiment, the semiconductor integrated circuit device may comprise another port section. The other port section may have a function of not converting a voltage.
When an external device (an input device, an output device, and an input/output device, or another semiconductor integrated circuit device) has the same operating voltage as the circuit section of the semiconductor integrated circuit device of the present invention, signals are transferred through the other port section. When an external device has an operating voltage that differs from the operating voltage of the circuit section of the semiconductor integrated circuit device of the present invention, signals are transferred through the port section.
(26) In one embodiment, the other port section may be provided with a predriver and another driver, and may have a function as an output port.
(27) In one embodiment, the thickness of a gate insulating layer of the field effect transistor being a component of the other predriver, the thickness of the gate insulating layer of the field effect transistor being the component of the predriver, and the thickness of the gate insulating layer of the first field effect transistor being the component of the first part of the level shifter may be equal to one another. Also, the thickness of a gate insulating layer of the field effect transistor being a component of the other driver, the thickness of the gate insulating layer of the field effect transistor being the component of the driver, and the thickness of the gate insulating layer of the second field effect transistor being the component of the second part of the level shifter may be equal to one another. The gate insulating layers of field effect transistors in which the same voltage is applied to their gate electrodes may have the same thickness.
(28) In one embodiment, the second voltage may be greater than the first voltage; and the thickness of the gate insulating layer of the second field effect transistor may be greater than the thickness of the gate insulating layer of the first field effect transistor. Both the first field effect transistor and the second field effect transistor of the present invention can operate at high speed, while preventing breakage of gate insulating layers.
(29) A master slice type semiconductor integrated circuit device of another aspect of the present invention comprises a semiconductor substrate on which a circuit section is formed, and a port section that is connected with the circuit section and functions as at least an output port. In accordance with the embodiment, the port section has a function of converting a first voltage into a second voltage that differs from the first voltage. The port section includes a first section having a first field effect transistor, and a second section having a second field effect transistor. A gate insulating layer of the first field effect transistor has a film thickness that differs from a film thickness of a gate insulating layer of the second field effect transistor.
When the thickness of the gate insulating layer is unnecessarily large, the operation of the field effect transistor becomes slow because the channel forming speed slows down. In one embodiment, the gate insulating layer of the first field effect transistor in the first section has the thickness which differs from that of the gate insulating layer of the second field effect transistor in the second section. Therefore, the thickness of the gate insulating layer that matches a given voltage can be selected in the port section. The operating speed of the port section can thus be increased.
(30) In one embodiment, the port section may be provided with a predriver and a driver; a first voltage signal may be input into and output from the predriver; and the driver may have a function of converting the first voltage into a second voltage which differs from the first voltage, and the first voltage signal may be input into and a second voltage signal may be output from the driver.
(31) In one embodiment, the predriver may comprise the first section having the first field effect transistor; and the driver may comprise the second section having the second field effect transistor.
(32) In one embodiment, a region where the predriver is formed may be located between a region where the circuit section is formed and a region where the driver is formed.
(33) In one embodiment, on the semiconductor substrate, the region where the predriver is formed may be located outside the region where the circuit section is formed, and the region where the driver is formed may be located outside the region where the predriver is formed.